Heavyweight Champs

Posted: July 1, 2014

Extreme wakesports boats haul massive loads, so their engines have to be serious overachievers.

By: Alan Jones

Ski-boat engines have never had to work harder. Every year, state-of-the-art wakeboarding and wakesurfing boats extend the envelope when it comes to ballast and devices such as wedges that simulate weight by pulling the stern lower into the water. This year, the Tigé ARS was unveiled with an astounding 3,000 pounds of standard ballast — almost the weight of the Green Bay Packers starting 11-player offensive unit (3,084 pounds) — before adding another 15-plus human ballast bags, aka passengers.

Just a few years ago, the biggest and baddest ski-boat engines packed 409 hp. Now that’s merely the jumping-off point. Currently, there are four main players in the wakesports mega-engine arena: Indmar, PCM, Ilmor and Marine Power. MerCruiser builds inboard ski-boat engines, but its top gun, the Scorpion 350 DTS ECT, puts out 330 hp, which is adequate for medium-duty work but would be hard pressed to handle extreme ballast and passenger loads. Engines over 500 hp are exempt from being required to have catalytic converters, because they will likely be used for wakesurfing, but all the engines we cover here have them.


Ilmor MV8 7.4L

Engine Description: The Ilmor MV8 7.4L is based on the big-block GM V-8 that has the distinction of being the highest-horsepower normally aspirated (nonsupercharged), catalyzed engine in the watersports world. It’s also the only engine — marine or automotive — to currently use the 7.4L platform. It employs a cast-iron block with aluminum heads along with forged pistons, connecting rods and crankshaft. Ilmore uses Variable Valve Timing for enhanced performance at all rpm.

Horsepower: 522

Torque: 524 ft. lbs. @ 4400 rpm

Origin: The 7.4L began its run as the LS5 454 engine powering the 1970 Chevrolet Chevelle SS and Corvette models. It saw additional duty as the 7400 Vortec truck engine starting in 1996. Ilmor gained prominence when it teamed with Honda Performance Racing to become the sole engine supplier for the Indy Racing League from 2006-2011. Its reliability was legendary; for six years running, its engine powered every car in the Indianapolis 500, and during that time there were zero in-race engine failures.

Marine Engine Builder: Ilmor (ilmor.com)

Available On: MasterCraft (MV8 7.4L)

Specs

- Compression Ratio: 10.7:1
- Displacement: 7.4L (454 cu. in.)
- Bore and Stroke: 106 x 105 mm
- Weight: 1,085 lbs.
- Max RPM: 5800
- Fuel: 87 octane regular

General Motors LS3

Engine description: The LS3 is a normally aspirated (nonsupercharged) aluminum small-block 6.2L GM V-8 that uses hydraulic roller valve lifters with Variable Valve Timing.

Horsepower: 450

Torque: 445 ft. lbs. @ 4600 rpm

Origin: This is a GM Gen-IV 6.2L block that was a “blank slate” engine design used in Corvettes from 2008-2013 and Camaro SS models from 2010 to present.

Marine Engine Builders: PCM (pcmengines.com), Indmar (indmar.com), Ilmor and Marine Power (marinepowerusa.com)

Available On: Malibu and Axis (Indmar Monsoon 427), Tigé (Indmar S62), Centurion and Nautique (PCM ZR 450), Moomba and Supra (Indmar Assault 450), MasterCraft (Indmar LS3 450 and Ilmor MV8 6.2L)

Specs

- Compression Ratio: 10.7:1
- Displacement: 6.2L (376 cu. in.)
- Bore and Stroke: 103 x 93 mm
- Weight: 924 lbs.
- Max RPM: 5200
- Fuel: Premium preferred, not required

General Motors LSA

Engine Description: It’s a GM Gen IV supercharged 6.2L small-block V-8. It uses an overhead valve design rather than the dual-overhead cam configuration usually found on high-performance engines. The engine block is cast-aluminum 319-T5 alloy with cast-iron cylinder liners. The crankshaft is forged steel, and the pistons are a lightweight high-silicon hypereutectic aluminum alloy with oil-spray cooling. The supercharger is an Eaton Twin Vortices Series intercooled model that produces 9.0 psi of boost. Of the three engines covered here, it revs the highest and makes peak torque at the lowest rpm.

Horsepower: 550

Torque: 545 ft. lbs. @ 4000 rpm

Origin: The LSA is derived from the LS9 engine that powered the Corvette C6 ZR1. The LSA currently powers the Cadillac CTS-V, billed as the world’s fastest production sedan, which goes from 0-60 mph in 3.9 seconds and hits an electronically limited top speed of 179 mph (198 mph without).

Marine Engine Builders: PCM, Indmar and Marine Power

Available On: Tigé (Indmar S62 Supercharged), Malibu and Axis (Indmar Monsoon 572 SS), Supra (Indmar 6.2L LSA 550), Sanger (Indmar 6.2L Ultimate 550) MB Sports (Indmar 6.2L LSA Supercharged 550), Nautique (PCM XS 550 and XR 550) and Centurion (PCM XS 550)

Specs

- Compression Ratio: 9.1:1
- Displacement: 6.2L (376 cu. in.)
- Bore and Stroke: 103 x 92 mm
- Weight: 700 lbs.
- Max RPM: 6200
- Fuel: Premium fuel recommended, not required

Big News

Ford is back in the marine world after a 20-year absence. In November, a Supra powered by an Indmar 6.2L Ford block, which is offered in F-150 SVT Raptor and F-Series Super Duty trucks, was on display. Speculation that GM will eventually be phasing out all V-8s could make this an even more important development.
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